SmartSDR v2.0.17.96

purchased, downloaded & installed v2.x.x.xx; went smoothly and flawlessly on my W8.1 Dell XPS 8700 PC. i do have a question however; if the next 3 or 4 major release do not include any enhancements i need and so do not purchase those upgrades but then on v6.x.x.xx there is something i like. do i have to purchase all the previous upgrades up to and including the version that i like or can i just skip the previous versions and go right to the version i like?